Welded joint for hot water tanks



Oct. 19, 1943. w. G. MARTIN WELDED JOINT FOR HOT WATER TANKS Filed Nov.21, 1941 Wesley GMartin INVENTOR. 5W

ATTORNEY I Patented Oct. 19, 1943 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to hot water tank construction and moreparticularly to the joining together of the heads and shell of a hotwater tank which parts are lined with a protective corrosion resistantmaterial such as ceramic enamel or' galvanizing to prevent corrosionwhile in service.

The main object of the present invention is to provide a durable jointbetween the head and shell of a hot water tank by a novel attachment ofthe head to the shell.

Referring to the drawing, there is illustrated a hot water storage tankhaving a generally cylindrical shell I and an upper head 2 and a lowerhead 3.

The heads 2 and 3 are each respectively disposed at opposite ends of theshell i to provide the circumferentially welded joints 4 and 5 when theheads are welded to the shell upon assem bly.

The shell I and heads 2 and 3 are made of any suitable metal. The shellis cylindrical throughout its entire extent and the heads are preferablyconcave.

The-interior surfaces of the shell I and the heads 2 and 3 are linedwith a protective mate rial, such as ceramic enamel 6 or galvanizing, to

protect them from corrosion by fluids contained within the tank. Theceramic enamel lining 6 is preferably employed and it is applied andfused to the interior surfaces of the heads and shell prior to assembly.If galvanizing is utilized it likewise is applied before assembly of thetank.

Suitable openings, not shown, may be provided in the tank for anydesired connections and attachments.

The joints 4 and 5 in the hot water tank illustrated are preferablysimilar. The description hereafter is therefore confined to the joiningof the head 2 to the shell I.

In manufacturing the head 2 into a concave structure, the skirt 1 of thehead 2 is formed into a substantially cylindrical'shape. In assemblingthe head and shell the skirt ll of the head 2 is inserted inside the endof the shell. In this manner of assembly the interior surfaces of theshell i overlie the outer surfaces of the cylindrical skirt l of thehead 2 for a substantial area.

in the preferred embodiment illustrated the skirt of the head 2protrudes outwardly a short distance farther than the end of the shell 5to provide an angular seat into which the weld metal of the joint 3 maybe deposited. In the modified embodiment illustrated by Fig. 3 the endof the head 2 extends co-extensively with the end of the shell i and noangular seat for the deposit of weld metal is formed. The shell may alsoprotrude a short distance beyond the skirt of head 2 to provide anangular seat for weld deposit To prevent injury to the joint d by thecirculation. of fluid to the weld metal deposited at the joint, a gasket5:; is preferably disposed, in both the embodiments illustrated, in thearea between the interior surface of the shell i and the outer surfaceof the skirt :7 of the head 2. The outer end of the gasket 8 is removedfrom the end of the shell 11 a slight distance in both embodiments.

The gasket 3 is corrosion resistant and also heat resistant in quality,such as an asbestos or glass fiber gasket or rubber or plasticcomposition. It is of a substantial thickness and may be employed in hotwater tanks having either a ceramic enamel or galvanized lining.

In addition to preventing circulation of fluid to the welded joint i,the gasket 3 protects the respective linings of the shell l and the head2 from injury during assembly as it separates the linings of each partwhich would ordinarily contact each other when the head 2 is insertedwith-- in one end of the shell l.

A relatively small sized metallic ring or wire 9 is disposed over theouter end of the gasket 8 between the interior surface of the shell land the outer surface of the skirt l of the head 2. The metallic ring 9is preferably of corrosion resistant metal or alloy such as a chromiumalloy steel and is employed in both of the embodiments illustrated. Withthe ring 9 in this po sition the head 2 and the sheel i are Weldedtogether at the joint 1 by the deposit of weld metal to seal the tankagainst leakage from within.

In the preferred embodiment the weld metal at the joint 43 is depositedby an electric arc in the angular seat formed in assembling the tank byextending the skirt of the head a short distance outwardly from the endof the shell. In the modified form the Weld metal at the joint 4 isdeposited on the respective ends of the head 2 and the shell 5 to sealthe tank against leakage, or the end edges of the head and shell and thering 9 may be melted and fused together by an electric carbon arewithout the deposition of additional weld metal.

The ring 9 effectively protects the gasket 8 disposed between the head 2and the shell I from injury by the heat of the welding arc. It alsoprevents inclusions in the weld metal deposited at the joint 4 from thegasket 8 should the gasket be melted by the welding arc. The ring 9becomes fused with the weld metal and forms a part of the joint.

In manufacturing the hot water tank illustrated the shell of the tank isrolled from sheet metal into a generally cylindrical shape and thenwelded along its longitudinally extending seam.

The heads are next formed into a concave shape with the skirt portionsthereof extending straightly in a substantially cylindrical shapesimilar to that of the shell.

The interior surfaces of the heads and shell are then preferably sprayedwith a ceramic enamel material and fused by heat to protect the interiorof the tank from corrosion by the fluids contained therein while thetank is in service.

The interior surfaces covered With the ceramic material include theopposed surfaces of the shell and heads.

In the next operation heat and corrosion retially cylindrical skirts ofthe heads while the heads are forced into place. In the preferred embodiment this locates the edges of the heads a short distance outwardlyfrom the ends of the shell. In the modified embodiment the edges of theheads are disposed co-extensively with the ends of the shell. In eithercase the edges of the heads may be said to be adjacent the respectiveend edges of the shell. The forcing of the heads into the ends of theshell compresses the gaskets between the interior surfaces of the shellI and the outer surfaces of the cylindrical skirts of the heads atpositions slightly removed from the respective edges of the shell andthe heads. The rings 9 are next applied and the circumferential welds 4and 5 are made to seal the joints between the heads and shell.

The gaskets keep the liquids within the tank from circulating in contactwith the exposed areas in and near the respective Welds. The gaskets areparticularly effective in retarding the flow of contained'liquids to thejoints 4 and 5 area in which the shell overlies the relativelycylindrical skirts of the heads. The gaskets also fill up anyirregularities in the linings of the heads and shell in the region wherethe latter meet as well as substantially eliminating the problem ofmanufacturing tolerances as to the relative dimensions of the heads andshell.

In turn the wire rings 9 disposed over the ends of the gaskets betweenthe respective heads and ends of the shell protect the gaskets from thedirect action of the welding arc and prevent the consequent melting andforming of inclusions in the Weld deposit.

sistant gaskets 8 are assembled on the substandue to their substantialextent in the considerable The structure made by the invention in themanner described provides a hot water tank with joints of very superiorquality. The welding of the joints seals the tank in the region of thejoints against leakage, and injury to the weld metal by corrosion fromthe fluid contained in the tank is prevented by employment of thegaskets. The wire ring disposed over the outer ends of the gasketsinsures that the gaskets will not be injured by the heat of the weldingarc and provides a base for receiving the are deposited weld metal.

Various embodiments of the invention may be employed within the scope ofthe accompanying claims.

I claim:

1. In a hot water storage tank, a head interiorly lined to protect thesame from corrosion and having a substantially cylindrical skirt, ashell similarly lined, a weld joining said head and shell together, acorrosion resistant member disposed between the meeting surfaces of theshell and head to prevent circulation of fluid to the weld, and acorrosion resistant metallic ring member secured in said welded joint atthe outer end of said corrosion resistant member.

2. A hot Water storage tank or similar structure, comprising a headinteriorly lined to protect the same from corrosion and having asubstantially cylindrical skirt, a shell similarly lined, the interiorsurface at one end of the shell being juxtaposed to the outer surface ofthe said skirt for a substantial overlapping area, a corrosion resistantmember of substantial thickness provided between the said skirt andopposing surface of the shell, a metallic ring member disposed at theouter end of said member, and a circumferential weld fusing said ringmember and the edges of the head and shell together.

3. A hot water storage tank or similar structure, comprising a concavehead interiorly coated with a ceramic enamel lining to protect the samefrom corrosion and having a cylindrical skirt, a shell similarly lined,the interior lined surface at one end of the shell being juxtaposed tothe outer lined surface of the said skirt for a substantial overlappingarea, a corrosion resistant member of substantial thickness providedbetween said skirt and the opposing surface of the shell, a metallicwire ring disposed at the outer end of said member, and acircumferential Weld fusing said ring and the adjacent edges of the headand shell together to complete the joint.

4. A hot Water storage tank or similar structure, comprising a concavehead interiorly coated with a ceramic enamel lining to protect the samefrom corrosion and having a substantially cylindrical skirt, a shellsimilarly lined, the interior lined surface of one end of the shellbeing juxtaposed to the outer lined surface of the said skirt for asubstantial overlapping area and with the end of the skirt extendingoutwardly a slight distance from the end of the shell to form an angularseat, a corrosion resistant gasket of substantial thickness providedbetween the said skirt and the opposing surface of the shell, a metallicwire ring disposed between the outer end of the said gasket and saidangular seat, and a deposit of weld metal in said angular seat to sealthe tank at the joint between the head and shell.

WESLEY G. MARTIN.

